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Friday, 20 August 2010

Pair Usefully and Code Effectively

Pairing is of real value when two developers work with each other in a such a manner that they allow the other person to teach and learn new ways of working. This mutual learning process will ensure that the competency of the team will grow uniformly. In my current job we almost never work alone we always pair. Recent retrospectives have been focussing on how we get the most out of our pairing sessions. Some developers said we don’t swap pairs enough, there were questions about how and when do we determine it is a good time to swap pairs.

Well there is probably no hard and fast rule on pairing but some of the things we seem to recognise in a team are as follows.

1. Story Champs - A story owner or champion should be present on the story who will see the story go through the board

2. Story Progress - Having a story champion will allow you to swap pairs across a story reasonably well without affecting the progress of the story.

3. Keyboard Policy – More often than not this is a reason for frustration among developers in a pairing session. Use TDD to pair effectively.

Eg. Pair made of Dev A and Dev B.

Dev A writes test to fail – Red

Dev B implements code to pass the test – Green

Dev A refactors the code

Alternate between the devs in this cycle will ensure pairing sessions are not driven by just one dev

4.Pairing Overdrive - If at any point during a pairing session one of the two seem to be dictating code for more than a few minutes ( I call this overdrive mode). You should really stop pairing and determine if the pairing session is useful and how it can be made useful , the dev who is on overdrive mode should really take the initiative to bring his/her pair up to speed on the story they are working on and discuss any gaps in each others understanding.. get away from the computer go for coffee break.. really helps.

5. Check-in frequency – When we pair due to reasons beyond our control one of the two dev may have to leave at any time before the other, frequent check-ins will allow you to make sure your CI is effective and also that you can switch machines quickly and effectively.

6. Computer Policy - if a pair is working on machine and dev who owns the computer has to leave, the other dev should be able to continue working on the story ..In such a situation it helps to leave the computer unlocked till your pair can make a check-in and then pull the changes on his computer and continue work, locking your computer and leaving could really be annoying to some one who really wants to continue work.

7. Early Birds –If you come in earlier than your pair, instead of just picking up the story and continuing work it helps to look at your CI server and fix any broker builds. If you do work on the story do make sure you explain what has been done and how far you have progressed so your pair gets up to speed, else you end up with Pairing Overdrive.

8. Privacy Policy – If you are working on your pairs machine and when your pair is not around do not snoop around there mail or respond to IM that they receive even for fun, what seems to be fun may turn out to be an annoyance. Finally there is absolutely no need to get personal during a pairing session, every developer has his own style and strengths it is important to respect that , for all you know they might be really skilled in areas you are not so good yourself..

After every stand up it makes sense to discuss who can swap pairs. Infact before a stand up it helps to be in a checked in state if you want to make sure your team can swap pairs every day